upub/utils/mdhtml/lib.rs

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Rust
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use html5ever::{tendril::SliceExt, tokenizer::{BufferQueue, TagKind, Token, TokenSink, TokenSinkResult, Tokenizer}};
use comrak::{markdown_to_html, Options};
pub type Cloaker = Box<dyn Fn(&str) -> String>;
#[derive(Default)]
pub struct Sanitizer {
pub cloaker: Option<Cloaker>,
pub buffer: String,
}
pub fn safe_html(text: &str) -> String {
Sanitizer::default().html(text)
}
pub fn safe_markdown(text: &str) -> String {
Sanitizer::default().markdown(text)
}
impl Sanitizer {
pub fn new(cloak: Cloaker) -> Self {
Self {
buffer: String::default(),
cloaker: Some(cloak),
}
}
pub fn markdown(self, text: &str) -> String {
self.html(&markdown_to_html(text, &Options::default()))
}
pub fn html(self, text: &str) -> String {
let mut input = BufferQueue::default();
input.push_back(text.to_tendril().try_reinterpret().unwrap());
let mut tok = Tokenizer::new(self, Default::default());
let _ = tok.feed(&mut input);
if !input.is_empty() {
tracing::warn!("buffer input not empty after processing html");
}
tok.end();
tok.sink.buffer
}
}
impl TokenSink for Sanitizer {
type Handle = ();
/// Each processed token will be handled by this method
fn process_token(&mut self, token: Token, _line_number: u64) -> TokenSinkResult<()> {
match token {
Token::TagToken(tag) => {
if !matches!(
tag.name.as_ref(),
"h1" | "h2" | "h3"
2024-08-11 13:48:53 +02:00
| "hr" | "br" | "p" | "b" | "i" | "s"
| "blockquote" | "pre" | "code"
| "ul" | "ol" | "li"
| "img" | "a"
) { return TokenSinkResult::Continue } // skip this tag
self.buffer.push('<');
if !tag.self_closing && matches!(tag.kind, TagKind::EndTag) {
self.buffer.push('/');
}
self.buffer.push_str(tag.name.as_ref());
if !matches!(tag.kind, TagKind::EndTag) {
match tag.name.as_ref() {
"img" => for attr in tag.attrs {
match attr.name.local.as_ref() {
"src" => {
let src = if let Some(ref cloak) = self.cloaker {
cloak(attr.value.as_ref())
} else {
attr.value.to_string()
};
self.buffer.push_str(&format!(" src=\"{src}\""))
},
"title" => self.buffer.push_str(&format!(" title=\"{}\"", attr.value.as_ref())),
"alt" => self.buffer.push_str(&format!(" alt=\"{}\"", attr.value.as_ref())),
_ => {},
}
},
"a" => {
let any_attr = !tag.attrs.is_empty();
for attr in tag.attrs {
match attr.name.local.as_ref() {
"href" => self.buffer.push_str(&format!(" href=\"{}\"", attr.value.as_ref())),
"title" => self.buffer.push_str(&format!(" title=\"{}\"", attr.value.as_ref())),
"class" => if attr.value.as_ref() == "u-url mention" {
self.buffer.push_str(" class=\"u-url mention\"")
},
_ => {},
}
}
if any_attr {
self.buffer.push_str(" rel=\"nofollow noreferrer\" target=\"_blank\"");
}
},
_ => {},
}
}
if tag.self_closing {
self.buffer.push('/');
}
self.buffer.push('>');
},
Token::CharacterTokens(txt) => self.buffer.push_str(txt.as_ref()),
Token::CommentToken(_) => {},
Token::DoctypeToken(_) => {},
Token::NullCharacterToken => {},
Token::EOFToken => {},
Token::ParseError(e) => tracing::error!("error parsing html: {e}"),
}
TokenSinkResult::Continue
}
}